Returning from Flex/ActionScript 3 Responder objects - apache-flex

I need to return the value from my Responder object. Right now, I have:
private function pro():int {
gateway.connect('http://10.0.2.2:5000/gateway');
var id:int = 0;
function ret_pr(result:*):int {
return result
}
var responder:Responder = new Responder(ret_pr);
gateway.call('sx.xj', responder);
return id
}
Basically, I need to know how to get the return value of ret_pr into id or anything that I return from that function. The responder just seems to eat it. I can't use a public variable somewhere else because this will be running multiple times at once, so I need local scope.

This is how I'd write a connection to the AMF server, call it and store the resulting value. Remember that the result won't be available instantly so you'll set up the responder to "respond" to the data once it returns from the server.
public function init():void
{
connection = new NetConnection();
connection.connect('http://10.0.2.2:5000/gateway');
setSessionID( 1 );
}
public function setSessionID(user_id:String):void
{
var amfResponder:Responder = new Responder(setSessionIDResult, onFault);
connection.call("ServerService.setSessionID", amfResponder , user_id);
}
private function setSessionIDResult(result:Object):void {
id = result.id;
// here you'd do something to notify that the data has been downloaded. I'll usually
// use a custom Event class that just notifies that the data is ready,but I'd store
// it here in the class with the AMF call to keep all my data in one place.
}
private function onFault(fault:Object):void {
trace("AMFPHP error: "+fault);
}
I hope that can point you in the right direction.

private function pro():int {
gateway.connect('http://10.0.2.2:5000/gateway');
var id:int = 0;
function ret_pr(result:*):int {
return result
}
var responder:Responder = new Responder(ret_pr);
gateway.call('sx.xj', responder);
return id
}
This code is never going to get you what you want. You need to use a proper result function. The anonymous function responder return value will not be used by the surrounding function. It will always return 0 in this case. You are dealing with an asynchronous call here, and your logic needs to handle that accordingly.
private function pro():void {
gateway.connect('http://10.0.2.2:5000/gateway');
var responder:Responder = new Responder(handleResponse);
gateway.call('sx.xj', responder);
}
private function handleResponse(result:*):void
{
var event:MyCustomNotificationEvent = new MyCustomNotificationEvent(
MyCustomNotificationEvent.RESULTS_RECEIVED, result);
dispatchEvent(event);
//a listener responds to this and does work on your result
//or maybe here you add the result to an array, or some other
//mechanism
}
The point there being using anon functions/closures isn't going to give you some sort of pseudo-syncronous behavior.

Related

Flex unit aysnc problem: Error: Asynchronous Event Received out of Order

I am writing test cases to test function with flexunit 4. I am using aysnc method.
But when I add two or more asyncHandlers to the instance. I meet the problem: Error: Asynchronous Event Received out of Order. How to resolve this problem? Thanks.
Code snippets:
[Test(order=1, async, description="synchronize content on line")]
public function testSynchronizeContentOnline():void
{
var passThroughData:Object = new Object();
var asyncHandler1:Function = Async.asyncHandler(this, authFailureHandler, 60000, null, timeoutHandler);
var asyncHandler:Function = Async.asyncHandler(this, authSuccessHandler, 60000, null, timeoutHandler);
caseManager.addEventListener(CaseAuthEvent.AUTH_SUCCESS,
asyncHandler);
caseManager.addEventListener(CaseAuthEvent.AUTH_FAILURE,
asyncHandler1);
caseManager.authenticate("admin", "admin");
trace('test');
}
private function timeoutHandler(event:Event):void
{
Assert.fail( "Timeout reached before event");
}
private var authFailed:Boolean = false;
private function authFailureHandler(event:CaseAuthEvent, passThroughData:Object):void
{
trace("authFailure:" + event.type);
authFailed = true;
}
private var authSucceed:Boolean = false;
private function authSuccessHandler(event:CaseAuthEvent, passThroughData:Object):void
{
trace("authSucceed:" + event.type);
authSucceed = true;
Assert.assertTrue(true);
}
That would be because you're adding order to your test cases, which is seems something else is dispatching before the first one is complete. To quote the ordering part of the flex unit wiki:
Your tests need to act independently of each other, so the point of
ordering your tests in a custom way is not to ensure that test A sets
up some state that test B needs. If this is the reason you are reading
this section, please reconsider. Tests need to be independent of each
other and generally independent of order.
Which I completely agree with. There should not be any order in your tests. The tests themselves sets the state of what needs to be done.
Your test will work if you test success and fail separately. So basically have 2 tests, one adds an async handler for your events success, the other for the events fail. Here is an example of the 2 tests as I would approach them...
[Test(async)]
public function testEventSuccess():void
{
var passThroughData:Object = new Object();
var asyncHandler:Function = Async.asyncHandler(this, authSuccessHandler, 60000, null, timeoutHandler);
caseManager.addEventListener(CaseAuthEvent.AUTH_SUCCESS,
asyncHandler);
caseManager.authenticate("admin", "admin");
}
[Test(async)]
public function testEventFailure():void
{
var passThroughData:Object = new Object();
var asyncHandler:Function = Async.asyncHandler(this, authFailureHandler, 60000, null, timeoutHandler);
caseManager.addEventListener(CaseAuthEvent.AUTH_FAILURE,
asyncHandler);
caseManager.authenticate("admin", "admin");
}
Remember to make a new instance of your caseManager in your set up function and its good practice to remove ref to it in the tearDown as the simple code snippet shows, I've just assumed the caseManager is of type CaseManager.
[Before]
public function setUp():void
{
caseManager = new CaseManager();
}
[After]
public function tearDown():void
{
caseManager = null;
}

Flex applying the sort/filter on an arraycollection without dispatching event

I have a object that is extended from arraycollection. This object has to access and manipulate the arraycollections source object. When this happens, the local sorted/filter copy of data goes out of sync with the source data. To line things up correctly, the sort/filter needs to be re-applied.
To do this normally, you would call refresh() on the arraycollection, but this also broadcasts a refresh event. What I want is to update the sort/filter without dispatching an event.
Having looked into the ArrayCollection class, I can see it is extended from ListCollectionView. The refresh function
public function refresh():Boolean
{
return internalRefresh(true);
}
is in ListCollectionView and it calls this function
private function internalRefresh(dispatch:Boolean):Boolean
{
if (sort || filterFunction != null)
{
try
{
populateLocalIndex();
}
catch(pending:ItemPendingError)
{
pending.addResponder(new ItemResponder(
function(data:Object, token:Object = null):void
{
internalRefresh(dispatch);
},
function(info:Object, token:Object = null):void
{
//no-op
}));
return false;
}
if (filterFunction != null)
{
var tmp:Array = [];
var len:int = localIndex.length;
for (var i:int = 0; i < len; i++)
{
var item:Object = localIndex[i];
if (filterFunction(item))
{
tmp.push(item);
}
}
localIndex = tmp;
}
if (sort)
{
sort.sort(localIndex);
dispatch = true;
}
}
else if (localIndex)
{
localIndex = null;
}
revision++;
pendingUpdates = null;
if (dispatch)
{
var refreshEvent:CollectionEvent =
new CollectionEvent(CollectionEvent.COLLECTION_CHANGE);
refreshEvent.kind = CollectionEventKind.REFRESH;
dispatchEvent(refreshEvent);
}
return true;
}
annoyingly, that function is private and so is unavailable to and class that extends ListCollectionView. Also, a lot of what is in the internalRefresh function is private too.
Does anyone know of a way to call internalRefresh from a class that extends ArrayCollection? Or a way of stopping the refresh event from being dispatched when refresh is called?
My (read:hack) solution to this:
addEventListener(CollectionEventKind.REFRESH, handlerHack, true);
The true adds this listener onCapture, before anyone else gets to act on the event.
Before you call the collection.refresh() to update sort/filter, set a boolean flag to true.
discardRefreshEvent = true;
myCol.refresh();
In the listener...
private function handlerHack(evt:CollectionEvent):void
{
if (discardRefreshEvent)
{
evt.stopImmediatePropagation();
discardRefreshEvent = false;
}
}
Disclaimer: Haven't done this exact use before (have implemented similar functionality with other events), also only guessing on Event types/names.
maybe you could extend ArrayCollection, listen to the refresh event and call stopImmediatePropagation() on it when it is fired ? I would start with this...
Good luck :-)

Flex/AS3 - calling a function dynamically using a String?

Is it possible to call a function in AS3 using a string value as the function name e.g.
var functionName:String = "getDetails";
var instance1:MyObject = new MyObject();
instance1.functionName(); // I know this is so wrong, but it gets the point accross:)
UPDATE
The answer from #Taskinoor on accessing a function is correct:
instance1[functionName]();
And to access a property we would use:
instance1[propertyName]
instance1[functionName]();
Check this for some details.
You may use function.apply() or function.call() methods instead in the case when you dont know whether object has such method for instance.
var functionName:String = "getDetails";
var instance1:MyObject = new MyObject();
var function:Function = instance1[functionName]
if (function)
function.call(instance1, yourArguments)
I have created the following wrappers for calling a function. You can call it by its name or by the actual function. I tried to make these as error-prone as possible.
The following function converts a function name to the corresponding function given the scope.
public static function parseFunc(func:*, scope:Object):Function {
if (func is String && scope && scope.hasOwnProperty(funcName)) {
func = scope[func] as Function;
}
return func is Function ? func : null;
}
Call
Signature: call(func:*,scope:Object,...args):*
public static function call(func:*, scope:Object, ...args):* {
func = parseFunc(func, scope);
if (func) {
switch (args.length) {
case 0:
return func.call(scope);
case 1:
return func.call(scope, args[0]);
case 2:
return func.call(scope, args[0], args[1]);
case 3:
return func.call(scope, args[0], args[1], args[2]);
// Continue...
}
}
return null;
}
Apply
Signature: apply(func:*,scope:Object,argArray:*=null):*
public static function apply(func:*, scope:Object, argArray:*=null):* {
func = parseFunc(func, scope);
return func != null ? func.apply(scope, argArray) : null;
}
Notes
Call
The switch is needed, because both ...args and arguments.slice(2) are Arrays. You need to call Function.call() with variable arguments.
Apply
The built-in function (apply(thisArg:*, argArray:*):*) uses a non-typed argument for the argArray. I am just piggy-backing off of this.

Can I get some advice on JavaScript delegates?

I'm rusty with delegates and closures in JavaScript, and think I came across a situation where I'd like to try to use one or both.
I have a web app that behaves a lot like a forms app, with fields hitting a server to change data on every onBlur or onChange (depending on the form element). I use ASP.NET 3.5's Web Services and jQuery to do most of the work.
What you need to know for the example:
isBlocking() is a simple mechanism to form some functions to be synchronous (like a mutex)
isDirty(el) checks to make sure the value of the element actually changed before wasting a call to the server
Agent() returns a singleton instance of the WebService proxy class
getApplicationState() passes a base-64 encoded string to the web service. This string represents the state of the application -- the value of the element and the state are passed to a service that does some calculations. The onSuccess function of the web service call returns the new state, which the client processes and updates the entire screen.
waitForCallback() sets a flag that isBlocking() checks for the mutex
Here's an example of one of about 50 very similar functions:
function Field1_Changed(el) {
if (isBlocking()) return false;
if (isDirty(el)) {
Agent().Field1_Changed($j(el).val(), getApplicationState());
waitForCallback();
}
}
The big problem is that the Agent().Field_X_Changed methods can accept a different number of parameters, but it's usually just the value and the state. So, writing these functions gets repetitive. I have done this so far to try out using delegates:
function Field_Changed(el, updateFunction, checkForDirty) {
if (isBlocking()) return false;
var isDirty = true; // assume true
if (checkForDirty === true) {
isDirty = IsDirty(el);
}
if (isDirty) {
updateFunction(el);
waitForCallback();
}
}
function Field1_Changed(el) {
Field_Changed(el, function(el) {
Agent().Field1_Changed($j(el).val(), getTransactionState());
}, true);
}
This is ok, but sometimes I could have many parameters:
...
Agent().Field2_Changed($j(el).val(), index, count, getApplicationState());
....
What I'd ultimately like to do is make one-linen calls, something like this (notice no getTransactionState() calls -- I would like that automated somehow):
// Typical case: 1 value parameter
function Field1_Changed(el) {
Field_Changed(el, delegate(Agent().Field1_Changed, $j(el).val()), true);
}
// Rare case: multiple value parameters
function Field2_Changed(el, index, count) {
Field_Changed(el, delegate(Agent().Field1_Changed, $j(el).val(), index, count), true);
}
function Field_Changed(el, theDelegate, checkIsDirty) {
???
}
function delegate(method) {
/* create the change delegate */
???
}
Ok, my first question is: Is this all worth it? Is this harder to read but easier to maintain or the other way around? This is a pretty good undertaking, so I may end up putting a bounty on this one, but I'd appreciate any help you could offer. Thanks!
UPDATE
So, I've accepted an answer based on the fact that it pointed me in the right direction. I thought I'd come back and post my solution so that others who may just be starting out with delegates have something to model from. I'm also posting it to see if anybody wants to try an optimize it or make suggestions. Here's the common Field_Changed() method I came up with, with checkForDirty and omitState being optional parameters:
function Field_Changed(el, args, delegate, checkForDirty, omitState) {
if (isBlocking()) return false;
if (!$j.isArray(args) || args.length == 0) {
alert('The "args" parameter in Field_Changed() must be an array.');
return false;
}
checkForDirty = checkForDirty || true; // assume true if not passed
var isDirty = true; // assume true for updates that don't require this check
if (checkForDirty === true) {
isDirty = fieldIsDirty(el);
}
if (isDirty) {
omitState = omitState || false; // assume false if not passed
if (!omitState) {
var state = getTransactionState();
args.push(state);
}
delegate.apply(this, args);
waitForCallback();
}
}
It handles everything I need it to (check for dirty, applying the application state when I need it to, and forcing synchronous webservice calls. I use it like this:
function TransactionAmount_Changed(el) {
Field_Changed(el, [cleanDigits($j(el).val())], Agent().TransactionAmount_Changed, true);
}
cleanDigits strips out junk characters the user may have tried to type in. So, thanks to everyone, and happy coding!
OK, few things:
Delegates are extremely simple in javascript since functions are first class members.
Function.apply lets you call a function with an array of arguments.
So you can write it this way
function Field_Changed(delegate, args)
{
if (isBlocking()) return false;
if (isDirty(args[0])) { //args[0] is el
delegate.apply(this, args);
waitForCallback();
}
}
And call it as:
Field_Changed(Agent().Field2_Changed, [el, getApplicationState(), whatever...]);
I have been using the following utility function that I wrote a long time ago:
/**
* #classDescription This class contains different utility functions
*/
function Utils()
{}
/**
* This method returns a delegate function closure that will call
* targetMethod on targetObject with specified arguments and with
* arguments specified by the caller of this delegate
*
* #param {Object} targetObj - the object to call the method on
* #param {Object} targetMethod - the method to call on the object
* #param {Object} [arg1] - optional argument 1
* #param {Object} [arg2] - optional argument 2
* #param {Object} [arg3] - optional argument 3
*/
Utils.createDelegate = function( targetObj, targetMethod, arg1, arg2, arg3 )
{
// Create an array containing the arguments
var initArgs = new Array();
// Skip the first two arguments as they are the target object and method
for( var i = 2; i < arguments.length; ++i )
{
initArgs.push( arguments[i] );
}
// Return the closure
return function()
{
// Add the initial arguments of the delegate
var args = initArgs.slice(0);
// Add the actual arguments specified by the call to this list
for( var i = 0; i < arguments.length; ++i )
{
args.push( arguments[i] );
}
return targetMethod.apply( targetObj, args );
};
}
So, in your example, I would replace
function Field1_Changed(el) {
Field_Changed(el, delegate(Agent().Field1_Changed, $j(el).val()), true);
}
With something along the lines
function Field1_Changed(el) {
Field_Changed(el, Utils.createDelegate(Agent(), Agent().Field1_Changed, $j(el).val()), true);
}
Then, inside of Agent().FieldX_Changed I would manually call getApplicationState() (and encapsulate that logic into a generic method to process field changes that all of the Agent().FieldX_Changed methods would internally call).
Closures and delegates in JavaScript:
http://www.terrainformatica.com/2006/08/delegates-in-javascript/
http://www.terrainformatica.com/2006/08/delegates-in-javascript-now-with-parameters/

Passing values between functions

Hi All is there any way to locally define a variable in a function and then pass it to the oher function. I mean to say is it possible the pass a local value from one function to other function.
Somebody Please suggest me the solution.
Thanks in advance
Or it's that simple or you meant something else:
private function function1():void
{
var localVariable:String = "this is local variable of function1()";
function2(localVariable);
}
private function function2(string:String):void
{
trace(string);
}
function1();
or use global variable as temporary storage:
private var globalVariable:String = "";
private function function1():void
{
var localVariable:String = "this is local variable of function1()";
globalVariable = localVariable;
}
private function function2():void
{
trace(globalVariable);
}
function1();
function2();
zdmytriv is right.
Although, you can also make default variables, like so:
(Modifying zdmytriv's code)
private function function1():void
{
var localVariable:String = "this is local variable of function1()";
function2(localVariable);
function2(); //You don't have to enter a default argument
}
private function function2(string:String = "something else"):void
{
trace(string);
}
This would trace:
this is local variable of function1()
something else
A little off topic, but good to know.
Primitives in Flex are passed by value, where complex objects are passed by reference. You can use this to pass objects around without scoping a variable outside the functions themselves. For instance:
private function function1():void {
{
var localVar:Object = {value:"test"};
trace(localVar.value);
function2(localVar);
trace(localVar.value);
}
private function function2(obj:Object):void
{
obj.value = "new value";
}
This would trace:
test
new value
Which reflects the fact that function2 receives the parameter "obj" by reference, as a pointer to the original "localVar" object. When it sets the .value field, that change is reflected in function1.
I just thought I'd point that out.

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